1. Field of the Invention
The present invention relates in general to electric motors, and particularly to axial gap motors wherein a rotor and a stator are coaxially arranged leaving a certain gap therebetween. More specifically, the present invention relates to a rotor used in such axial gap motor and a method of producing the rotor.
2. Description of the Related Art
Hitherto, in the field of electric motor vehicles, hybrid motor vehicles and the like, various high power electric motors have been practically used, which are, for example, an interior permanent magnet synchronous motor (IPMSM) that has permanent magnets embedded in a rotor and a surface permanent magnet synchronous motor (SPMSM) that has permanent magnets placed on a surface of the rotor. Actually, because of practical usage of reluctance toque besides magnet torque, the above-mentioned motors, viz., IPMSM and SPMSM, can exhibit a high efficiency and thus a high output.
Some of the above-mentioned motors are of an axial gap type wherein a rotor and a stator are coaxially arranged leaving a certain gap therebetween. Due to its inherent construction, the motors of such axial gap type can have a thinner structure, viz., reduction in an axial length of entire construction of the motor, and thus such compact and powerful motors have been used as prime movers of the above-mentioned motor vehicles. One of such motors is shown in Japanese Laid-open Patent Application (Tokkai) 2002-204559.